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WARNINGOVERDOSE, COMBINATIONS, & WITHDRAWAL CAN BE FATAL
High doses alone or ordinary doses in combination with other depressants can fatally stop breathing. After prolonged dependency, stopping suddenly can cause seizures, delirium, or death.
Methaqualone
2-Methyl-3-o-tolyl-4(3H)-quinazolinone
Quaalude, Sopor, Mandrax, Parest, Ludes
Methaqualone is a sedative-hypnotic depressant of the quinazolinone class.citation needed Its sedative properties were first identified by researchers in the 1950s, and it was patented in the United States in 1962. During the 1970s, it saw widespread medical use for insomnia and muscle relaxation, as well as significant recreational popularity within the counterculture and disco scenes. Though largely discontinued as a pharmaceutical, it continues to be produced clandestinely, particularly in South Africa. Illicit methaqualone products are often adulterated, sometimes with other CNS depressants.
Dosage & Duration
Dosage
Doses are population estimates that vary widely between individuals.
Threshold~75 mg
Light75-150 mg
Moderate150-300 mg
Strong300-500 mg
Heavy500+ mg
Duration
Onset20-45 minutes
Peak2-4 hours
Offset1-2 hours
After Effects2-24 hours
Total4-8 hours
Half-life
4-60 hours
Subjective Effects
Legacy content. A statistically backed ontology from Mindstate Design Labs is coming soon.
Effects vary widely by individual, dose, and context.
Physical
Cognitive
Visual
Pharmacology
Pharmacodynamics
Methaqualone acts primarily as a positive allosteric modulator of GABA-A receptors, enhancing the inhibitory chloride currents generated by GABA.citation needed Some minor direct agonist activity has also been observed, though it is not comparatively significant.1 Its binding site is located at the transmembrane β(+)/α(-) subunit interface, distinct from those of benzodiazepines, barbiturates, and neurosteroids, though it may partially overlap with the etomidate binding site.citation needed Methaqualone may also function as a negative allosteric modulator at certain GABA-A receptor subtypes, and is therefore considered a mixed GABA-A receptor modulator.1 It shows negligible affinity for a wide array of other potential targets, including other receptors and neurotransmitter transporters.citation needed
Pharmacokinetics
Methaqualone is readily absorbed from the gastrointestinal tract and distributes into body fat, liver, and brain tissue via plasma. Peak plasma concentrations are reached approximately 2 hours after oral administration.2 Its elimination half-life has been variably reported, with estimates ranging from approximately 4 hours to as long as 60 hours.
Metabolitesnone documented yet
Dangerous
Highest riskThese combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.
DissociativesStimulants
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
1,2-BenzodiazepineAbametapirAcetazolamideAcetophenazineAgomelatine
Tolerance
Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.
Full Tolerance
Tolerance to sedative-hypnotic effects develops quickly, often after only a few days of repeated dosing. Physical dependence can develop within about two weeks when moderate doses are used every day. Tolerance to euphoric effects appears to develop faster than tolerance to respiratory depression, substantially increasing overdose risk when users raise doses to regain earlier subjective effects.
Baseline Reset
1-2 weeks of abstinence in the absence of further consumption. Avoiding tolerance buildup generally requires spacing doses by several days up to about a week.
Half Tolerance
Approximately 3-7 days after cessation of use.
Cross Tolerance
GABAergic depressants, Barbiturates, Other sedative-hypnotics
Harm Potential
Addiction & Dependence
Psychological
HighMethaqualone is described as extremely addictive with high abuse potential.citation needed Psychological dependence is very common with regular use, particularly at doses over 600 mg per day. Users report severe cravings for the drug persisting for extended periods after cessation.
Physical
HighPhysical dependence develops rapidly, with daily use of even moderate doses producing addiction within a couple of weeks.citation needed Withdrawal symptoms include restlessness, irritability, insomnia, tremors, nausea, vomiting, abdominal cramps, and muscle twitches. Severe withdrawal can involve mental confusion, delirium, hallucinations, high fever, and epileptic-like seizures that can be fatal.
Toxicity
Respiratory
Respiratory depression is a significant effect at higher doses and can progress to respiratory arrest in overdose; the combination with other depressants substantially increases this risk.citation needed
Cardiovascular
Cardiac effects including reduced heart rate and blood pressure occur during use; cardiac arrest is possible in severe overdose.citation needed
Renal
Kidney failure has been reported as a consequence of severe overdose.
Psychosis Risk
Paranoia, panic, and anxiety can occur during use, particularly at certain doses. More severe psychiatric effects including mental confusion, delirium, nightmares, and hallucinations are primarily associated with withdrawal rather than acute intoxication.citation needed
Seizure Risk
Seizures represent a significant risk with methaqualone both in overdose and during withdrawal from chronic use.citation needed Convulsions have been documented in both circumstances, with withdrawal seizures being potentially fatal. The drug has anticonvulsant properties at normal doses, but tolerance develops to this effect with repeated administration.
History & Culture
Discovery and Development
Methaqualone was first synthesized in India in 1951 by M.I. Gujral as part of a research program seeking antimalarial compounds. Although the substance proved ineffective against malaria, researchers identified its hypnotic properties by 1955. A subsequent pharmacological study in 1957 confirmed…
Legality
International
Methaqualone is internationally controlled in Schedule II of the 1971 Convention on Psychotropic Substances. It is not listed in the schedules of the 1961 Single Convention or the 1988 Convention schedules checked.
By Country
Illegal11
United StatesIllegalOriginally approved by the FDA in 1965 with minimal controls. Placed in Schedule II in 1973 following concerns about abuse potential. Moved to Schedule I in June 1984 after Congress passed legislation specifically targeting methaqualone.56 Under current law, it is illegal to manufacture, buy, possess, or distribute without a DEA license. Lemmon, the final domestic manufacturer, ceased production in November 1983.
AustraliaIllegalThe Therapeutic Goods (Poisons Standard—June 2026) Instrument 2026 lists methaqualone in Schedule 9. Schedule 9 substances are prohibited by law except when required for approved medical or scientific research, or for analytical, teaching or training purposes; the Standard states that scheduling is implemented through State and Territory legislation.
CanadaIllegalMethaqualone and its salts are listed in Schedule III of Canada's Controlled Drugs and Substances Act, which has been in force since May 14, 1997. Unless authorized under the regulations, possession, production, trafficking, importation and exportation are prohibited; Schedule III offences carry statutory penalties set by the Act.
GermanyIllegalControlled under the Betäubungsmittelgesetz.17 Manufacturing, importing, possessing, selling, or transferring without license is prohibited. Initially sold over-the-counter in the 1960s before prescription requirements were introduced in 1963 following reports of misuse.
IndiaIllegalMethaqualone is listed as a Schedule I psychotropic substance under the Narcotic Drugs and Psychotropic Substances Rules, 1985. Its manufacture, sale, purchase, possession, transport, import, export, consumption, and use are permitted only for the limited medical, scientific, training, enforcement, or other purposes specified in Chapter VIIA. The current Schedule I was substituted with effect from 13 October 2006; contraventions involving a psychotropic substance are punishable under section 22 of the Narcotic Drugs and Psychotropic Substances Act, 1985.
IsraelIllegalMethaqualone is a dangerous drug under Israel's Dangerous Drugs Ordinance [New Version], 5733-1973, which lists it in Part 2 of the First Schedule by the chemical name 2-methyl-3-O-tolyl-4-(3H) quinazoline. The Ordinance prohibits possession and use of a dangerous drug except as authorized by the Ordinance, its regulations, or a Director's licence, and it separately requires a Director's licence to cultivate, manufacture, produce, prepare, or extract one.
NetherlandsIllegalOpiumwet33
Methaqualone (methaqualon) is listed in Lijst I of the Dutch Opiumwet. The Act prohibits importing or exporting, preparing, processing, selling, supplying, transporting, possessing, and manufacturing List I substances; intentional possession may be punished by up to six years’ imprisonment or a fifth-category fine, intentional preparation, processing, sale, supply, transport, or manufacture by up to eight years, and intentional import or export by up to twelve years.
PortugalIllegalDecreto-Lei n.º 15/93, de 22 de Janeiro36
Methaqualone (metaqualona) is listed in Tabela II-C of Decreto-Lei n.º 15/93, Portugal’s controlled-psychotropics regime, in force since 1993. Its cultivation, production, manufacture, sale, distribution, import, export, transport and unauthorized possession are controlled; unauthorized trafficking in substances in tables I–III is punishable by 4 to 12 years’ imprisonment.
RussiaIllegalGovernment of the Russian Federation Decree No. 681 of 30 June 199837
Methaqualone is a List I psychotropic substance under Government Decree No. 681 of 30 June 1998. Its circulation in the Russian Federation is prohibited under Russian legislation and Russia's international treaties. The List I controls also extend to its possible isomers, salts, ethers, and mixtures containing List I substances.
SwedenIllegalMethaqualone (metakvalon) is listed in Förteckning II of the Swedish Medicines Products Agency’s narcotics schedules and is narcotics under Swedish law. Unauthorised possession, use, manufacture, transfer, acquisition for transfer, and non-personal handling are narcotics offences; ordinary narcotics offences carry imprisonment of up to three years, with separate rules for minor and aggravated offences. Import and export require a permit in each individual case.
Controlled / restricted13
ColombiaRestrictedResolución 315 de 202014
Methaqualone is a specially controlled psychotropic substance in Colombia under Resolución 315 de 2020, which places it in Lista Verde, Lista II. The resolution subjects the listed substances to state control and extends that control to mixtures and products containing them; handling them is governed by the Fondo Nacional de Estupefacientes registration and control regime.
DenmarkRestrictedBekendtgørelse om euforiserende stoffer15
Methaqualon is listed in Denmark's order on euphoric substances. The listing places it under Danish controlled-substance rules.
FinlandRestrictedValtioneuvoston asetus huumausaineina pidettävistä aineista16
Metakvaloni is included in Finland's list of substances regarded as narcotics. It is controlled through Finland's narcotics legislation.
IrelandRestrictedMisuse of Drugs Regulations 201722
Methaqualone is listed in Schedule 2 of Ireland's Misuse of Drugs Regulations 2017. Its production, supply, importation and exportation are prohibited except as the Regulations permit.
ItalyRestrictedD.P.R. 9 ottobre 1990, n. 309, Tabelle26
Metaqualone is included in Table III of Italy's controlled-substances tables. It is subject to the national narcotic and psychotropic control regime.
New ZealandRestrictedMisuse of Drugs Act 1975, Schedule 234
Methaqualone is listed in Schedule 2 of New Zealand's Misuse of Drugs Act 1975. Schedule 2 substances are Class B controlled drugs.
NorwayRestrictedForskrift om narkotika35
Metakvalon is listed in Norway's narcotics regulation as P II. It is controlled under the Norwegian narcotics schedule.
SingaporeRestrictedMisuse of Drugs Act 1973, First Schedule38
Methaqualone is listed as a controlled drug in Singapore's Misuse of Drugs Act. It is regulated under that Act's controlled-drug provisions.
South AfricaRestrictedDrugs and Drug Trafficking Act 140 of 1992, Schedule 239
Methaqualone, including Mandrax, is listed in Schedule 2 to South Africa's Drugs and Drug Trafficking Act. It is controlled under that Act.
South KoreaRestricted마약류 관리에 관한 법률 시행령 별표 440
메타쿠알론 is listed as a psychotropic drug in South Korea. Its listing is in Schedule 4 to the Enforcement Decree of the Narcotics Control Act.
SwitzerlandRestrictedMethaqualon is listed as a controlled substance in the Swiss EDI Ordinance on the Lists of Narcotic Drugs, Psychotropic Substances, Precursors and Auxiliary Chemicals (BetmVV-EDI), in the combined classification a+b. Its manufacture, acquisition, possession, supply, import, export and trade are consequently subject to the Swiss narcotics-control authorization and oversight regime rather than ordinary unrestricted handling. The official consolidated ordinance was updated by the 15 May 2025 amendment.
UkraineRestrictedПостанова Кабінету Міністрів України № 77047
Метаквалон is named in Ukraine's list of narcotic drugs, psychotropic substances and precursors. The listing places it in the national controlled-substances system.
United Arab EmiratesRestrictedUAE controlled substances Schedule No. 648
Methaqualone is listed in Schedule No. 6 of the United Arab Emirates controlled-substances schedules. It is subject to the UAE's controlled-substances regime.
Prescription3
JapanPrescription onlyCabinet Order Designating Narcotics, Plants Containing Narcotic Raw Materials, Psychotropics, and Narcotic and Psychotropic Raw Materials (Cabinet Order No. 238 of 1990)272829
Methaqualone and its salts are designated psychotropics under Article 4(73) of Japan's Cabinet Order Designating Narcotics, Plants Containing Narcotic Raw Materials, Psychotropics, and Narcotic and Psychotropic Raw Materials. The Narcotics and Psychotropics Control Act licenses commercial psychotropics handlers, limits retail transfer to a person with a psychotropics prescription, and criminalizes unauthorized import, export, manufacture, formulation, or packaging. The Ministry of Health, Labour and Welfare's controlled-substances list, dated 12 December 2024, independently identifies methaqualone as a psychotropic.
MexicoPrescription onlyMethaqualone (metacualona) is a Grupo II psychotropic substance under Article 245 of Mexico's Ley General de Salud. Grupo II substances have therapeutic value but are treated as a serious public-health concern and, when incorporated into medicines, are supplied only on medical prescription under the Law's psychotropic-substances controls. The Diario Oficial de la Federación's 9 September 1985 official list records metacualona in Grupo II.
References
Source Pages
Citations
- Harriet Hammer, Benjamin M. Bader, Corina Ehnert, Christoffer Bundgaard, Lennart Bunch, Kirsten Hoestgaard-Jensen, Olaf H.-U. Schroeder, Jesper F. Bastlund, Alexandra Gramowski-Voß, & Anders A. Jensen. (August 2015). A Multifaceted GABAA Receptor Modulator: Functional Properties and Mechanism of Action of the Sedative-Hypnotic and Recreational Drug Methaqualone (Quaalude). Molecular Pharmacology, 88(2), 401–420. https://doi.org/10.1124/mol.115.09929112
- John M. Clifford, James H. Cookson, & Phyllis E. Wickham. (1974). Absorption and clearance of secobarbital, heptabarbital, methaqualone, and ethinamate. 16(2), 376-389. https://doi.org/10.1002/cpt19741623761
- The rise and fall of the Quaalude: The forgotten drug. Liberty House Clinic (n.d.). https://www.libertyhouseclinic.co.uk/blog/society/the-rise-and-fall-of-the-quaalude-the-forgotten-drug/1
- Therapeutic Goods (Poisons Standard—June 2026) Instrument 2026. legislation.gov.au (n.d.). https://www.legislation.gov.au/F2026L00633/latest/text1
- Therapeutic Goods (Poisons Standard—June 2026) Instrument 2026. legislation.gov.au (n.d.). https://www.legislation.gov.au/F2026L00633/latest/details1
- Suchtgiftverordnung (SV), Anhang IV.1. ris.bka.gv.at (n.d.). https://www.ris.bka.gv.at/eli/bgbl/ii/1997/374/ANL4/NOR402674551
- Suchtgiftverordnung (SV), Anhang IV.1. ris.bka.gv.at (n.d.). https://www.ris.bka.gv.at/geltendefassung.wxe?abfrage=bundesnormen&gesetzesnummer=10011053&ShowPrintPreview=True1
- Controlled Drugs and Substances Act. laws-lois.justice.gc.ca (n.d.). https://laws-lois.justice.gc.ca/eng/acts/C-38.8/section-sched95602.html1
- Controlled Drugs and Substances Act. laws-lois.justice.gc.ca (n.d.). https://laws-lois.justice.gc.ca/eng/acts/C-38.8/section-4.html1
- Controlled Drugs and Substances Act. laws-lois.justice.gc.ca (n.d.). https://laws-lois.justice.gc.ca/eng/acts/C-38.8/section-5.html1
Article Status
Step 1 · Automated synthesisAn autonomous workflow built by Josie Kins compiled this article's foundation from information published across the web.
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Recent changes7 human edits · latest
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24 January 2026
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
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